Project Summary/Abstract Biomimetic mineralization for calcified tissue regeneration remains challenging. The intimate spatiotemporal relationship between mineral, collagenous matrix and soluble protein of a calcified tissue is critical to achieve the biomineral-matrix ultrastructure necessary for its function, yet this relationship is poorly understood and difficult to recreate. Strategies have adapted and mimicked the natural process of biomineralization, mostly using polyanionic acid partially imitating non-collagenous proteins (NCPs) to induce formation of amorphous nanoprecursors for intrafibrillar collagen mineralization. The effectiveness of these approaches is partial, and new analogue of NCPs is yet to be found to improve biomimetic mineralization. Recent substantial evidences suggest phosphorylation of NCPs as the key modification that grants these proteins a power to regulate biomineralization. The phosphoproteins secreted into the extracellular matrix have a high affinity for calcium, thus enable mineral-binding and inhibition to regulate mineralization. The therapeutic application of phospho- proteins/peptides for biomimetic mineralization, nonetheless, is still tentative due to the difficulties in synthesis and purification of these molecules. The long-term goal of my research is to utilize a new category of biomimetic, peptide-like polymers, poly-N-substituted glycines, or peptoids, and provide a promising pathway to functionally restore diseased calcified tissues. The objectives of this study will focus on the development of phosphonate- containing peptoids (phospho-peptoids) to imitate specific mineral-binding, phosphorylated motifs in natural phosphoproteins. I will investigate the biological functions of the phospho-peptoids to mineralize collagenous tissues such as affected dentin as a model, which requires biomimetic mineralization for restoration as it doesn't repair physiologically. Peptoids have potent biological functions and great biocompatibility, and exhibit benefits over both synthetic peptides and reconstituted or purified proteins for the ease of design and synthesis, purity, resistance to undesirable proteolysis, and excellent solubility in many common solvents, potentially very beneficial nanomaterials for therapeutic application. My recent publication reported the use of an inhibitory carboxylate-peptoids as one of the analogues for biomimetic mineralization, and confirmed the favorable advantages of peptoids in dentin remineralization, such as their comparable biofunctionality, adaptable design and engineering for our needs. Given the key role of phosphorylation of NCPs in biomineralization, a greater level of recovery of dentin lesion is expected with phospho-peptoids than carboxylate-peptoids. This proposal will be carried with three aims: 1) Select phospho-peptoids from a library; 2) Apply selected phospho-peptoids to mineralize collagenous matrix and tissues; and 3) Translational application of phospho-peptoids in mineralized tissue - dentin caries system. The use of phospho-peptoids will improve biomimetic tissue mineralization at a nanometric molecular scale of precision. I expect to reveal valuable properties of phospho-peptoids to be the new therapeutic materials for precision treatments.